Honing machine



1944; v G. CROMPTON, JR 2,356,223

HONING MACHINE Filed June 12, 1942 10 Sheets-Sheet l g- 1944- G. C ROMPTON, JR 2,356,223

HONING MCHINE Filed. June 12, 1942 l0 Sheets-Sheet 2 1w-eh Aug. 22, 1944. G. CROMPTON, JR 2,356,223

HONING MACHINE Filed June 12, 1942 10 Sheets-Sheet s Aug. 22, 1944. G. CROMPTON, JR 2,356,223

- HONING MACHINE Filed June 12, 1942 l0 Sheets-Sheet 4 g. g Gag &

Aug. 22, 1944;'

G. CROMPTON, JR

HONING MACHINE Filed June 12, 1942 10 Sheets-Sheet 5 IIHHI ll lllllllllHHIIHIHHIIHIIHIIII HIHIIHIIHHIIH g- 2, 1944. e. CROMPTON, JR 23 52 HONING MACHINE Filed Jun 12, 1942 10 Sheets-Sheet 7 253 I 254 251 Y I Z- Aug. 22, 1944. CRQMPTQN, JR. I 2,356,223

HONING MACHINE Filed June 12, 1942 1o Sheets-Sheet s rim-F G. CROMPTON, JR 2,356,223

HONING' MACHINE Filed Jurie 12, 1942 10 Sheets-Sheet 9 g- 1944. e. CROMPTON, JR 7 6,

HONING MACHINE Fiied June 12; 1942 10 Sheets-Sheet 1o I! IIIIIIIlIIlIlIl/IIIIIIIIIIIIIIIIIIII/II!!! IIIIIIII I III!!! FIE/E Patented Aug. 22, 1944 UNITED STATES PATENT OFFICE 2,350.22:

HONING MACHINE George (h'ompton, in, Worcester, Mass, assignor to Norton Company, Worcester, Mass., a corporation of Massachusetts Application June 12, 1942; Serial No. 446,743

17 Claims.

The invention relates to honing machines. One object of theinvention is to provide a honing machine for accurately bringing the several bores of a casting to the same size with a smooth 1 finish. Another object of the invention is to accomplish the preceding object within commercial limits so that but a single size of piston need be provided. Another object of the invention is to accelerate the production of honed multiple cylinder bore castings. Another object of the invention is to increase the emciency of multiple internal honing.

Another object-oi. the invention is to give the operator controls whereby he can equalize various specific honing operations in a multiple honing job from time to time and be accurately informed of the progress of the honing operations.

Another object of the invention is to provide a honing machine utilizing the maximum skill of an operator; giving him instrumentalities to aid him in making the best possible use of his machine and his tools.

Another object of the invention is to provide a control whereby the operator can instantly stop the expansion of a given honing tool of a plurality of honing tools in a multiple honing machine and expand it again as desired. Another object of the invention is to provide a honing machine with a gauge which will, give the size of particular bores being honed continuouslyduring the honing operation.

Another object of the invention is to provide a compact honing tool which is expanded by screw wedge means powered by the. main driving motor and controlled by an airbrake, the whole being so organized as to permit of remote control. Another object of the invention is to provide a honing machine and. apparatus permitting the honing tools to be collapsed by reversing the main driving motor which rotates the Another object of the invention is to pr de multiple gauging apparatus which at all times gives the size of the several bores being honed together with remote controls for controlling the honing operation in. each bore and for collapsing all of the tools and running up the honing head whenever desired.

Another object of the invention is to provide .instrumentalities which can be incorporated in objectswill be in part obvious or in part pointed out hereinafter.

the several air brakes The invention accordingly consists in the features of construction, combinations of elements, arrangements of parts, and in the several steps and relation and order of each of said steps to one or more of the others thereof, all as will be illustratively described herein, and the scope of the application of which will be indicated in the following claims.

, In the accompanying drawings illustrating one of many possible embodiments of the mechanical features of this invention,

Figure 1 is a front elevation of a honing machine constructed in accordance with my invention:

Figure 2 is a view, partly in side elevation and partly in vertical section, of the upper part of the machine, on a somewhat larger scale than Figure 1; f

Figure-3 is a plan view of the top of the machine, on the same scale as Figure 2, certain casing covers being removed better to show the parts; Y p

Figure 4 is an axial sectional view of the work piece and support and a side elevation of a honing tool, the parts being shown on a larger scale than in anyof the preceding views;

Figure 5 is an axial sectional view, on a still larger scale, of a honing tool;

Figures 6 and '7 are cross sectional views taken, respectively, ure 5;.

Figure 8 is an axialsectional view, taken along the line H of Figure 2;

Figure 9 is a fragmentary side elevation illustrating certain of the controlling devices for the hydraulic reciprocating mechanism;

Figure 10 is an axial sectional view, "on an enlarged scale, ofa certain solenoid operated valve; Figure 11 is an enlarged view, partly in side elevation and partly in vertical section, illustrating the control for stopping the head in its upper position;

Figure 12 is a wiring diagram of the main driving motor and reversing switch;

Figure 13 is an elevation of the control panel and ammeters:

Figure 14 is a schematic view containing an electrical diagram for the variable condenser gauges, an electrical diagram for the solenoid control valves, and an air pressure diagram for for the individual honing tools;

Figure 15 is a greatly enlarged vertical sectional view of the gauging apparatus, taken on the line lI-II ofFigure 6;

on the lines 0-6 and 1'I of Fi and its connected cas Figure 16 is a sectional view on the same scale as Figure 15, taken on the line lG-IG of Figure 15;

Figure 17 is a greatly magnified fragmentary sectional view showing the elements of the condenser;

Figure 18 is a view on the same section as Figure 15 but on a. different scale and showing the upper parts of the honing tool, andv especially the wiring connections;

Figure 19 is a perspective view of a fixed contact member.

The invention is illustrated applied to a honing machine of the general type disclosed in U. S. Letters Patent No. 1,783,019 of Albert M. Johnson. The invention, so far as it resides in the honing tool itself, is shown embodied in a modification of the honing toolillustrated by U. S. Letters Patent No. 1,912,025 to Frederick G. Wacker and Herman W. Zimmerman. I shall hereinafter referto these patents, respectively, as the Johnson patcut and the Wacker patent.

As in the case of the Johnson patent, and referring now to Figure 1, the machine comprises a base I upon which is fixed an upright column 2 forwardly provided with a pair of vertical slideways 3. A work supporting table 4 having slidably adjustable guiding supports on .the way 3 is further supported from the base I by means of adjustable elevating screw standards 5. A piece of work is shown supported on the table comprising in the present instance a four-cylinder internal combustion motor block 6 suitably clamped upon an adapter block I which rests upon the table I. I

Referring to Figure 2, mounted upon the upper end of the colunm 2 is amain housing 8 having, as also shown in Figures 1 and 3, a pair of upright auxiliary housings 9 and I extending forwardly therefrom in spaced relation, the lower ends of which are positioned above the work supported on the table I. The auxiliary housings 9 and In each support a vertically positioned spindle driving shaft II. The spindle shafts and their associated parts being similarly constructed, will be described as to one only and similar reference numerals applied to both. The shaft II is preferably provided with a thrust collar l2 which engages an anti-friction bearing I3 secured to the upper end of a guide sleeve I4. The sleeve II extends through the lower end of the auxiliary housing 9 and is provided with spaced bearings I and a sleeve I I which is keyed to the shaft. The sleeve I1 :is supported in ball bearings I3 and I9 which are supported in a portion oi the housing 9, as clearly shown in Figure 2.

Secured to the upper end of the sleeve II and located in a casing 9a carried on top of and integral with the auxiliary housing 9, is a spur ures 2 and 3, and remembering that there are two bevel gears 26, they mesh with bevel gears 21 fastened to a cross shaft 28 in the housing I. As indicated in Figures 2 and 3, fastened to one end of the cross shaft 28 is a gear 32 which meshes with a gear 33 mounted on a shaft 34 which is journalled in part of the housing 9. The gear 33 is driven by a pinion gear 36 secured to a shaft 31 coupled to an armature shaft 33 of a direct current reversible motor 39 mounted on a suitable bracket 30 supported by a wall of the housing I. By means of the foregoing mechanism, the motor 3!! drives both of the spindle shafts II and can constitute reciprocatory guideways are secured to the upper wall of the head 63, each of the sleeves having an annular flange 54 positioned in an annular pocket provided in the upper wall of the head and secured thereto as by bolts. The spindle driving shafts II extend into the ends of the head 63, being supported at their lower e in ball bearings 65 secured in the lower en of the sleeves ll. 1

Still referring to Figure 8, fastened to th lower ends of the driving shafts I I are driving ears 66. These gears 66 mesh with gears iI fastened to short shafts 68 iournalled in the head 93. Each shaft 69 has likewise fastened to it a gear 69,. which meshes with gears II and II, respectively secured to spindle supporting socket members I2 and I3, the latter being carried in spaced ball bearings I4 mounted in bearing bosses I9 formed in the lower wall of the head 63. Thus each shaft II drives a pair of spindle supporting socket membersl2, I3 which are journalled in the head 63, and the sockets I2 and I3 are rotated in the same angular direction and at the same velocity as the gears III and II do gear 29 which meshes with a spur gear 2| mounted on a stub shaft 22 which is journalled in ball bearings 23 and 24 mounted in a bearing hub 25 extending between the auxiliary housing 9 9a. As shown in Figure 3, there is a correspo r$ing casing Ilia on top of the auxiliary housing I Figure '2, fastened to the shaft 22, is a bevel gear 26 9. Continuing now with ower end of the stub Comparing now Fignot mesh with each other but mesh with the driving pinion 69.

As shown in Figure 1, there are four socket members I2, I3 and they are located in pairs, each of the sockets I2 being located the same distance from adjacent sockets I3, although the space between sockets I2 is not always the same as the space between sockets I2 and I3. The spacing shown is the same as that of the cylinder bores in atypical internal combustion engine cylinder block 6, but other heads with different spacing of the gears and sockets may be substituted. Furthermore, the machine tool may be widened by adding additional auxiliary housings like the housings 9 and III and repeating the mechanism therein contained to drive any number of spindle sockets I2, I3 desired, thus if desired providing a machine of this type for the honing of six cylinder blocks, or'eight straight-in-line cylinder blocks.

Referring now to Figures 1 and 8, reciprocatory movement ofethe head 63 is accomplished by means of a hydraulically actuated piston ll located in a cylinder II which, as shown in Figure 1, is fastened to the housing 8 and located between the auxiliary housings 9 and III. A piston rod I3 of the piston I6 extends from the lower end of the cylinder II and is attached to the head as shownin Flguresl and aaoaaaa n; This piston'rod is further extends upwardly,

, movement of the valve and protect it against pos through the upper-cylinder head of the cylinder II andinto a balancing air cylinder I9 which,

of the casings 9a and l (notto the cover Plates 9b and lob). J

3, is bolted to the tops The cylinder 'II is supported on the housing 9 by brackets 80 and 9|. which are braced by means of tension rods 32 and 83. The upper and lower ends of the cylinder H are provided with ports 04 and 35 opening through the brackets and BI into commlmication with the interior of the cylinder. Referring now to Figure 9, there is provided a four-way controlling or reversing valve 90 having ports connected to pipes 01 and 98 which are connected to the ports 04 and 95. Pipe connections 99 and 99 to the valve 06 are respectivelyconnected with the pressure side and the suction side (or the sump) of an oil pump indicated in Figure 3 by the numeral 9|.

Referring again to Figure 9, the control valve 09 operates to direct fluid alternately into the pipes 31 and 33 tosend pressure fluid-to the opposite ends of the cylinder 11 to reciprocate the head 93. At any given time one of pipes 91 or 39 contains fluid under pressure while the other oneis the return pipe for the return of the fluid from the no-pressure end of the cylinder. The valve 09 contains a piston, not shown, the position of which is determined by a pilot valve 93 having pipe connections 94 and 95 with opposite ends of the four-way controlling and reversing valve 30. The pilot valve 93 likewise has pressure and exhaust pipe connections 96 and 91 with the pump 9|. The pilot valve 93 includes a longitudinally moving piston controlling the ports through the pipe connections with the ends of the reversing valve 96, and this piston is controlled by a piston rod 90. I do not herein illustrate or describe the details of the pistons and ports in valves 86 and 93, the same having not been described in the Johnson patent either, since pilot and reversing valve constructions are now well known to those skilled in this art and any suitable pilot and a reversing valves may be utilized, and so far as many features of my invention are concerned any other type of actuating, controlling and reversing mechanism might be substituted for" that herein described, for example, a mechanically operated and controlled mechanism of which ther are many types. Resuming the description of this particular controlling and reversing mechanism, and referring again to Figure 9, the piston rod 90 carries a spring stop device comprising a rod 99 pivotally mounted at one end in a block I00 secured to the piston rod-98. The rod 99 has fastened thereto in spaced ation a pair of blocks I 0| and I02 which have spring receiving recesses facing each other and holding springs I04 and I05. Between the blocks IM and I02 is a block I03 .which is engaged'by the springs I04 and I05, thus offering resilient resistance to the-movement of the block I03 along the rod 99. The block I03 is pivotally secured to a reversing lever I09 which is pivotally mounted on a stud I 01 projecting from a bracket I09 secured to the side wall'of the housing I0. The lever I06 extends to the other side. of the stud I01 and terminates in a reversing lug I09 protruding from a counterweighted portion I090 of the lever I09. The pilot valve controlling mechanism is constructed to permit the movement of the pilot valve with a slight overrun in the valve operating lever I06 ainst spring tension, to assure the complete sible damage by Jamming. In some respects the pilot valve is a substitute forgthe load and fire mechanism, arrow point and cam device, or the snapover detent, well known in machine tools for controlling a mechanical reversing mechanism and also used to some extent to control a main valve. Any one of such devices may be utilized to achieve a reversal of the rectilinear travel of the tools as distinguished from a mere stopping thereof.

The machine so far described is the machine of the Johnson patent and, except in combination with the other features hereinafter explained, is not my invention. In fact, any other suitable honing machine tool maybe substituted for the machine of the Johnson patent although my invention readily lends itself to incorporation in this machine. Although in the description which is to follow, some parts may be identified as parts of the Johnson machine, the operation and con-' trol as well as the several features of the machine are part of my invention, as will hereinafter appear.

Referring now to Figures 1 and 9, I provide a reciprocating control rod IIO which at the upper end passes through and is guided by a bracket III extending from the cover of the gear casing I0a. Adjustably fastened to this rod IIO are striking dogs H2 and H3, the'striking portions of which are disks and-arranged in the path of v the reversing lug I09. Also adjustably mounted on the rod H0 and intermediate the dogs I I2 and H3 is a shaped dog H4. This dog II4, when in the position shown in Figure 9, moves in the path of the lug I09 and will strike the lug I09 (as shown in Figure 9) to reverse the travel of the head 93. However, when the rod H0 is given a slight turn either manually or by an automatic mechanism hereinafter described, the striking portion of the dog' II4 is moved out of the path of the lug I 09. Y

Referring now to Figure 11, there is provided a hand lever H9 fastened to the lower end of the rod IIO by means of which the rod IIO may be manually turned to swing the striking portion of the dog H4 out of the path of the lug I09. Referring now to Figures 1 and 11, fastened to the rod IIO are thrust collars I I'I which secure it so far as vertical movement is concerned to a bracket H8 which is fastened to the side of the head 63. Therefore, the rod IIO moves upwardly and downwardly with the head 63. I provide a stop arm II9 fastened to and extending downwardly from the bracket H9 and extending into the path of movement of the hand lever Hi to prevent movement to the left (Fig. 1) of the hand lever IIG beyond the position shown in Figure 1. In the position of Figure l, the operating portion of the intermediate dog H4 is in the path of the lug I09.

The reciprocating movement of the head 93 is further controlled by a stop valve I22 (Figures 1 and 3) interposed in the main pressure line from the pressure pump 9| which normally allows oil to be directed under pressure to the fourway valve 06 but which may be moved to bypass the oil back to the suction side of the pump. When the valve I22 is so moved, the head 93 will come to a stop. This stop valve I22 is operated by an arm I23 connected to the valve stem I24 of the valve member of the stop valve I22. The arm I23 is mounted on a sleeve I25 which is joumalled on a rod I 29 extending between and journalled in brackets I21 and I23, the former anism fully described in the Johnson patent, the

operating lever I33 may be connected to actuate the lever I36 or it may be disconnected therefrom for independent control of the sleeve I25 and thereby the stop valve I22. Usually the two levers I33 and I36 are connected together and operate as a unit and thereby the controls more.

fully described hereinafter serve automatically to stop rotation of the spindle sockets I2 and I3 whenever the traverse of the head is automatically stopped in its upper position and, furthermore, the controls serve to stop thetraverse of the head in any position when the spindle sockets I2 and I3 stop rotating.

Referring now to Figures 1, 3 and 12, I provide an electric control to cause the honing tools hereinafter described to be raised out of the work piece by upward movement of the head 63 when desired by the operator. To the top of the cover of the gear casing I0a is fastened a solenoid I40 which has a core I connected by a link I42 with a lever I43 keyed to the rod H0. The rod H0 is splined at the top portion thereof to permit it to move through the lever I43, and the bracket I II provides a bottom and top thrust bearing for the lever I43, the'bracket III being forked, as shown in Figure 1. The other end of the lever I43 is connected by means of a spring I46 to a spring anchor I4I secured to the cover I0b of the gear casing I0a. In Figure 3 all the covers have been removed more clearly to show the gearing and other mechanisms. But the various parts including the bracket III, the spring I46, a sole,-

the head 63 in its withdrawn position at the finish of a honing operation and, therefore, I provide an additional mechanism automatically to operate the stop valve I22 just before the dog II3 would engage the lug I66. Therefore, when the machine is started up again, the dog I I3 first shifts the lug I09. to reverse the reciprocating mechanism. That is to say, the head 63 may first rise by a slight dist .nce, for example, a fraction of an inch before it descends to commence a honing operation..-

Referring now to Figures 1, 3 and 11, I provide an arm I50 having a hub I 5| fastened to the sleeve I25. The outer end of the arm I66 has a bore I52 receiving a spring I63 bearing against a movable pin I54 in the bore I52. There is a slot I55 in the top of the arm I56 through which projects an operating rod I56 secured to the pin I54. The operating rod I56 is provided with a knob I51 for convenient operation.

The bracket II8 has an inclined cam surface 460 which is in position to engage the pin I64, and when it does so it will swingthe arm I66 to the left, Figure 1, operating the valve I22 and stopping the head 63 by by-passing the pressure fluid. Figure 1 shows the cam surface I66 engaging the pin I54 and the head 63 is about to I stop, the arm I50 having been moved partially noid I40 etc. are shown in the position whichfor the' lever I43, the entire unit including the- 1 cover can be lifted vertically upward off the shaft IIO whenever it isdesired to remove the cover '50 SP1 of the gear casing I01; and the cover can, of course, be replaced by fitting the parts upon t e shaft H0 and then moving everything downwardly;

The spring I46 endeavors at all times to turn the rod H0 in a clockwise direction in plan view. The-force of this spring I46, therefore, keeps the handle II6 against the stop H9 and maintains the dog H4 in the path of thelug .the' lug I09 to reverse the direction of, travel but, as explained, it'can be moved out of the path of the lug I09 either manually by operation of the hand lever IIS or.by energization of the solenoid I40. The dog II3 will also reverse but not through the entire distance. This action preferably takes place in advance of the dog II3 striking the lug I69 so that the head is brought to a stop without reversing the pilot valve 93 and thereby the reverse valve 66. This precaution eliminates the possibility of the head being reversed and traveling downward to cause the hones to reenter the finished work piece. When the operator is ready to hone a new work piece, however, he may push the knob I5I rearwardly which will place the pin I54 behind the bracket II8, allowing the rod I26 to be partially rotated to reestablish the fluid pressure connections which will cause the head 63 to descend after a slight rise to cause the reversing action.

by pushing the lug I66 past the center point.

Referring now to Figure 2, the hones are units and are designated generally by the reference character I10. That is to say, the honing tools are completely removable from the machine and 31' die III having a tapered end portion fitting in a socket I2 or I3.

flexible couplings "3 the construction of which may be as described in the Johnson patent, or universal joints may be substituted, if desired. The provision of either one allows the honing tool I10 to adjust itself in the bore of the cy der block work piece 6, for it'must be understood that previous operations on a cylinder ,block do not bring the axes of theseveral bores info the same plane all exactly a given distance apart within the matter of a thousandth of an inch or fractions thereof which arPSignificant dimensions in a finishing operation of the nature performed by a machine of the invention.

Referring now to Figures 5 and 6, I have therein illustrated a honing tool which may be and preferably is constructed substantially in accordance withthe Wacker patent aforesaid. The operation thereof including the pneumatic brake to be described, however, is my own invention. I do not deem it necessary to describe the honing tool in detail (apart from the new features) since reference may readily be had to the Wacker patthe travel of the head 63, but I desire to stop is eat and, furthermore, many and varioustypes of self-contained tools. Each bone "6 has a The spindles or shanks III are connected to lower spindles II2 by means of honing tool instrumentalities may be substituted so far as my invention is concerned. Briefly, the Wacker patented hone includes an upper plate I18 which, however, I have formed as the lower part of a hollow spindle H811, and the Wacker patented hone includes a lower plate I18, and the plates I18 and IJMre connected by tie bars I11, as described in the Wacker patent. Whereas for a four-stickghone there are four tie bars I11 in the Wacker patented construction, I have replaced one of these with a somewhat thicker and heavier member I18 on one side and a similar member I18 on the other side in which I incorporate the bore diameter measuring apparatus to be presently described The plates I15 and I18 together with the tie bars I11 and the members I18 and I19 form a cage construction guiding carriers I80 upon which are detachably' mounted honing sticks I8I. Each carrier I80 has inclined surfaces I82 which are engaged by cones I83 mounted on a screw shaft I84 which extends through the upper plate I15 and is journalled in the hollow spindle 115a and is integral with the lower part,of the flexible coupling I13. Thus according tomy invention, and in this respect the construction and operation diifer from that of the Wacker patent, the screw shaft I84 is'the driving member so far as the honingv tools I10 are concerned. Garter springs I88 engage portions of the carriers I80 and removably hold the structure in assembled relation. The cones I83 are prevented from rotating with respect to the inclined surfaces I82 of the carriers I80 by means of splines I88 in thecones and projections I81 on the members 118 and I19 projecting into the splines. The bottoms of the splines argparallel to the axis of the honing tool so that the cones III are free to move vertically relative to the honing tools I10 and yet are non-rotatable with respect to the honing tool as a whole which means that they always rotate with it. It will now be seen that rotation of the screw shafts I84 causes rotation of the honing tools as a whole because the screw shafts -I84 tendto rotate the cones I83 and these cannot rotate without rotating the cages and the entire honing tools I10. This principle does not hold when the cones I88 are free to move downwardly. But the cones I89 are not free to move downwardly unless the carriers I80 can move outwardly, and during the honing operation the carriers are limited in their outward movement due'to contact of the sticks I8I with the bores of the work pieces.

But the very fact of contact of The cones I88 are, of course, threaded internally, and constitute nuts on the screw shaft I84.

The honing sticks I8I may be of any suitable type, for example, bonded abrasive consisting of any of the usual abrasives such as silicon carbide or alumina in .its various forms, also diamonds, and the bond may be of any desired type, for example, vitrified ceramic bond, resinoid bond ineluding natural and synthetic resins, rubber, or metal bond, for example, as descirbed in Van der Pyl Patent No. 2,072,051.

Referring now to Figures 4, 5 a nclg6, the upper part of the hollow spindle "in has a reduced diameter portion I90 which may be cylindrical and which is one-element of the brake referred to. The hollow spindle I15a further has a flange I9I. On top of the hollow spindle I15a is a washer I92 maintained in position by bolts I98. The brake surface of the portion I90, the flange I9I, and the washer I92 position an annular casing I95 which may be made out of sheet metal or the like and which is loosely fitted in the position shown so that it may be held'stationary while the hollow spindle I15a rotates. In Figure 2 is shown a metal bar I98 which is fastened to one of the bosses 15 and alsoto a casing I95, thus preventing the casing from rotating. The bar I98 is not so rigid but that slight eccentric motion of the casing I95 due to misalignment of the bores in the work piece is permitted. It will be understood that just as there isa brake mechanism for every honing tool, so also there is a holding bar I98 for every easing member I95,

Figure 7 shows a cross section of the casing I95. As therein shown, the casing I95 contains a rubber ring 200 surrounding a plurality of brake sectors 20I made of metal or any suitable material desirably having friction shoes 202 ce merited thereto. These friction shoes 202 may be made of leather, if desired. -When air under pressure is introduced into the chamber 208 formed by the casing I95 and the rubber ring 200, the rubber ring contracts, forcing the brake sectors 20I inwardly in radial directions, pressing the friction shoes 202 against the cylindrical surface of the reduced diamet r portion I90. Thus, by the expedient of introducing compressed air into the stationary chamber 202, a

braking force is exerted against the hollow spin dle I15a and the entire cage construction of the honing tool I10 which is connected to said holthe sticks ill with the bores of the work pieces causes resistance to turning of the honing tools and this in turn sets up a force derived from the screw shafts I84 tending to move the cones I 83 in a vertical direction. of course, the direction of rotation of the honing tools and the pitch of the screws I84 issuch that the normal honing rotative drive tends to expand the honing tools.

The net result of these forces is that the honing tools must rotate and at the same time they are and must be urged to expand which creates a honing pressure in each work piece cylinder. As will hereinafter be describedJ provide brakes for the hollow spindles I15a which will increase this honing pressure and I provide further means in the form of a reversing switch for reversing the direction of rotation of the armature of the motor 89, thus reversing the direction of rotation of all of the screw shafts I84 simultaneously, and when this is done and the brakes are applied the cones I88 are moved upwardly by the screw shafts I84 and all of the honing tools contract.

\ low spindle I15a; The invention provides means at the will of the operator for introducing air into any one or more of the chambers 203 or all 9 of them together and for exhausting it fromany one or more of the chambers 208or all of them together. r

Referring now to Figures 1, 8, 10 and 14, and

I first to Figure 1, the cylinder 19 contains air under pressure. This causes a constant force,

to be exerted against a piston 205 in the cylinder 19, thus exerting a constant upward force on the long vertical piston rod 18. This force is' calculated to be. approximately equal to the weight of the head 88 and all the vertically movable parts connected therewith, such as all of the honing tools I10 and the spindle driving shafts II and the sleeves I4 etc. According to the present invention I make use of the air pressure inthe cylinder-19 to actuate the brakes just described. As shown in Figure 1, the piston 205 has a U shaped passage 208, one end opening at the under side of the piston 205 into the cylinder 19 and the other end connecting to the inside of the piston rod 18 which is hollow. Re-

rn'bber washer 201 may be provided between the bottom of the screw threaded bore in the boss 208 and the bottom of the piston rod 18 which is externally screw threaded. Thus air under pressure is at all times in the pipes 2| l which are carried by the reciprocating head 63.

Referring now to Figure 1, the pipes 2Il branch and lead to a plurality of valves 2I 2. There is one valve 2I2 for each honing tool. Referring now to Figure 10, each valve 2I2 is part of valve controlapparatus constructed on a base 2I3. The valve 2I2 includes an air entrance port 2 formed in a screw threaded pipe connection '2I5 and an air port 2I6 which is connected to a chamber 203, the port extending through a screw threaded pipe connection 2I1; a poppet valve 2 I 8 having at one end a shank 2I9 and at the other end a shank 220; a spring 22I surrounding the.

shank 220, and a closure plug 222. The poppet valve 218 works in a chamber 223 in which. is a valve seat 224. valve 2I8 against the seat 224. However, abutting the shank 2 I9 is a solenoid core 225 made of iron or some other magnetic material and this is connected to a non-magnetic bar 226 which abuts the shank 221 of another poppet valve 228. in a valve chamber 229. The poppet valve 228 has a second shank 230 surrounded by a spring .23I which is backed up by a closure plug 232. The spring 23I is stronger than the spring 22I, so when a solenoid 235 surrounding the solenoid core 225 is not energized, the parts will be in the position shown in Figure 1.0 with the poppet valve 2I8 open and the p ppet valve 228 seated against a seat 238'. r

The chamber 229 has a port 231 entering it which extends through a threaded piping connection 238 and a port 239 extends from the right-hand side of the poppet valve 228 to the atmosphere. Referring now to Figure 1, pipes 240 extend from the casings I95 .upwardly and I branch and each pipe 240 is connected to each The spring 22I urges the poppet having, as better shown in Figure 13, pu'sh buttons 242 and 243. Each pair of push buttons 242, 243 controls a solenoid 235. When the but-. 7

tons 242 are pushed in, the circuits are open but when the buttons 243 are pushed in, the circuits are closed to energize the solenoids 235. As shown in Figure 14, the wiring is very simple and may consist of a positive line 244 and a nega- "tive line 245. The positive line 244 is connected described.

of the pipe connections H1 and 238 and, there- 1 fore, to thegports 2I6 and 231. -With the parts in the position shown in Figure 10, air under pressure from the cylinder 19 at the top of the machine is admitted to. the particular chamber 203 in a casing I95 controlled by that particular valve apparatus. However, when that particu lar solenoid 235 is energized, the iron core 225 is drawn inwardly and this forces open the poppet valve 228 and at the same time allows the poppet valve 2I8 to be closed by the spring 22I (assisted by the air pressure itself). This cuts off the air pressure from the particular ch trolled by that particular solenoid 235 and valve apparatus and opens up the chamber 203 to the atmosphere via, a pipe 240, a port 231, a. chamber 229 and exhaust port 239. So, therefore, to

her 203 con-.

sum up, when a particular solenoid 235 is un- I also provide a control for the driving motor 39 which rotates the honing tools, interlocked with center terminal 252 of a reversing switch and also by a connected line 253 to the fleld coils 254 of the motor 39. The negative line.255- is con- 'nected to the other center terminal 258 of'the reversing switch and by a connected line 251 to the other end of the field coil of the motor 38. One brush 25a of the motor 29' is connected by a conductor 259 to a pole 260 of the reversing switch. The other brush 26I of the motor 39 is connected by a conductor 262 to an adjacent pole 263 of the reversing switch. The usual cross wires 264 and 265 connect the poles 268 and 263, respectively, to opposite poles 268 and 261. The knives 268 of the reversing switch will also. en-

gage poles 269 and 210 connected by conductors 2H and 212 to the solenoid 240. The reversing above the push buttons 242, 243, as shown in Figure 13.

' In this embodiment of this invention, as shown in Figure 3, the pump 9| is independent of the motor 39 and may be driven by a motor 215 having a sprocket 216 on its armature shaft 211, the sprocket 216 driving a sprocket 218 by means of a chain 21.9, and the sprocket 218 being on the pump shaft 280.

According to the present invention, the honing operation is stopped by first stopping the motor 39. Owing to the friction on the stones Ill in the work piece bores, thehoning tools will quickly stop rotating. But it is desired that as the rotation dies, the reciprocatory traverse should also cease as otherwise the cylinder bores" might be scored by vertically moving but non-rotating sticks I8I.

shown in Figure 3 connected to the stop valve I22 already described. Referring now to Figure 3, upon the shaft 31 is fastened a collar 28I supporting pins 282 which mount arms 293 having slots 284 and, at the ends remote from the-pins 262, centrifugal balls 285. Mounted upon the shaft 31 also is a slidable collar 286 having pins 241 When, however, the shaft 31 slows down, a spring These controls are diagrammed So, therefore, I provide the governor,

I are splines 3 I 1.

290 pushes the collar 296 away from the gear 36. The link I3l is connected to an arm 29I resting on top of a casing cover On for part of the main housing 3. Referring now to Figure 2, the arm 29I is detachably fastened to a vertical shaft 292 mounted in a bearing 293 fastened to the casing 3. The shaft 292 extends downwardly and is fastened to a yoke 294 having rollers 295 extending into a groove 295 (see now Figure 3) in part of the collar 236. The groove 296'is wider than the rollers 295 to provide some lost motion. By reason of this mechanism, when the shaft 31 stops, the valve stem I24 is pushed inwardly which moves the stop valve I22 to traverse stopping position, thus stopping the reciprocation of the bones when their rotation is stopped.

Considering now the apparatus for measuring the size of the bores of the work pieces, reference may first be had to Figure 14 and from that figure, specific reference to Figures 1, 2, 4, 5, 6, 15,

opposite to it a short slot 3". These slots together will receive a screw driver by means of which I the cylindrical holder This adjusts the cylindrical holder back and forth in the member 300. Naturally" enough, extra washers 321 can be provided for large adjustments, but for small adjustments the washer 321 will be compressed more or less and this also prevents undesired change of the adjustment. To hold the movable contact member 302 from flying out altogether,- a cap 335 is screwed onto the end of the cylindricalholder 320 which is externally threaded at this point and the cap 335 will be contacted by the shoulder 336 which forms the boundary between the reduced diameter portion 3I6 and thefull diameter part of the movable contact member 302. The cap 335 may be prevented from accidental unscrewing by .means of a bendable piece of metal 331 which will 16 and 17 will disclose the detailed construction and arrangement. Each member I19 is cut out 4 to form guideways for a block 300 which. has a g pair of fixed contact members l and a mov-' able contact member 302., .The contacting nortions of the contact members 30I and 302 should be made of some very hard and wear resistant. material. An excellent material for this purpose is boron carbide B in molded form sold by Norton Company under the trade mark Norbidel' This can be molded into simple shapes and more complex shapes can be made by grinding it with a, diamond grinding wheel.

The fixed contact members 30I are illustrated in Figure 19. As therein shown, they consist of cylinders of boron carbide rounded at the ends .to form frusto-conical entering portions 305. Norbide can readily be molded into cylindrical form and the frusto-conical portions 305 can be formed on it by means of a diamond grinding wheel.

As shown in Figure 16, these fixed contact members 30I fit in partial cylindrical holes 306 in the block 300, The frusto-conical portions 305 contact the mouth of the work piece cylinder bore 'as the tool enters it and, therefore, push the block 300 inwardly against springs 3I0 which extend partly into the movable block 300 and partly into the member I19. The block 300 is pre-- vented from flying out altogether as, for example, prior to the time when the tools have entered the work piece bores by means of pins 3 projecting from the block 300 and into slots 3I2 in a portion 3 I 3 of the member I19.

Referring now to Figures 15, 16 and 18, the movable contact member 302 is also a cylinder of Norbide shaped as followsz-At the outer end is a spherical zone tip 3I5 which contacts the work piece bore. Next to that is a reduced diameter portion 3I6. On opposite sides of the cylinder All of these portions can be made with diamond wheels.

The movable contact member 302 fits with a sliding fit in a cylindrical holder 320. This cylindrical holder 320 has an enlarged diameter externally threaded portion 32I leaving a pronounced shoulder 322 and it in turn has a snug fit in a bore 325 in the-block 300. The bore 325 merges into a larger and internally threaded bore 326 into which the portion 32l screws.' A large rubber washer 321 fits between the shoulder 322 of 'the portion 32I and a seat 328 which joins the bores 325 and 326.

fit in any one of a number of holes 333 formed in the exterior cylindrical surface of the cylindrical member 320. The cap, of course, can be easily removed simply by bending the metal 331 with a pair of pliers.

The movable. contact member 302 is prevented J from rotating in the cylindrical holder 320 by means of a Woodruifkey 340 which fits in the spline 3 and also a short spline 3 in the bore of the cylindrical holder 320. The'bottomof the other spline 311 is silvered and base of the movable contact member 302 has a layer of silver 343; see Figure '17. The layer of silver 343 should connect'with the silver on the .bottom of the spline 3|! but should not extend quite to the cylindrical surface of the movable contact member 302. The movable contact member may be silvered as follows: The entire member is inserted in a silver solution, such as a solution used to make mirrors, and a good plate of silver is formed. Then those portions which it is not desired to be silvered have the silver removed therefrom. It would not be necessary tact member 302 and between it and the plane surface 345 constituting the bottom of the bore in the cylindrical member 320 is a rubber disk 346. The surface 345, the silver 343, and the rubber disk 34 6 constitute the elements of a condenser. High frequency current is. used and it is desired that the capacity of 'the condenser be relatively large as compared with the capacity of the circuit as awhole; hence the rubber 340 can be very thin, for example, of the order of-five to ten thousandths of an inch in thickness. This is possible because the relative motion of the movable contact member 332 between the start of the honing operation and-the finish thereof,

may be a matter of Considering now the circuit'which includes the condensers 343, 345, 346 which inJJhe diagrammatic views I give the numeral 350 as a whole,

The front or left-hand end of the cylinder holder 320 has a long slot 330 and diametrically and referring now to Figure 14,1 provide a suitable source of high frequency electricity 360 which is simply designated by the legend Electronic tube. high frequency generator. This source may have a frequency in megacycles and I do not need to describe such a generator since they are now known in the electronic art. One terminal 36I of the generator 360 is connected 320 can be tumed..

the right-hand insulating rings 3" surrounding and fastened to the hollow spindle "5a. 7

It is of some importance to point out the action and mechanical details of the electrical connections in this invention. It is desirable to have the capacity of the circuits (apart from the con- Y 'densers themselves) as low as possible. I,-the'refore, use ground for one part of the circuit to avoid two insulated wires side by side which would set up capacity. Referring now to Figure 1, a cable 315 can contain the conductor 366, constituting one side of the high frequency circuit.

This cable 315 is fastened to the movable head 83 and isalso fastened to the bracket 48 and forms a'variable loop as the head 63 moves up and down. It can also contain the wires 346 and 348 leading to the solenoids 235 because those are closed circuits not connected with. the high frequency circuits. It is also desired to avoid variable resistance represented by the oil films in the journals of the machine and, in fact, these journals themselves have capacity. The ground or base of the machine may, therefore, be connected to the movable'head 83 by means of a second hanging conductor315. The ground side of the circuit is now connected to the movable head 83 and yet. interposed therebetween and the rotating hollow spindle "5a. are the journals in the head which as aforesaid may constitute condensers and have a great deal of capacity. So, therefore, I provide a brush 311 contacting a metal ring 318 in the insulating ring 3" but which is connected to aground portion 388 to ground the current into the hollow spindle "5a whence by direct bolted connection it reaches the member I18. There is no appreciable amount of capacity in the jumping from the member I19 to the sliding block 388 because the springs 3|8 make a good electrical connection and the electricity can move into the cylindrical holder 328 which is in direct metallic contact with the block zoo and no oil film needs to be used between these parts.

Referring now to Figures 5, 15 and 18, I provide a terminal screw 38! having insulating rubber washers 382 and 383 between which are a pair of terminal rings 384, 385. The ring 384 has integral therewith a connecting terminal 386 soldered to the silver at the bottom of the spline 3I1. The ring 385 is the end of an insulated wire 398 which leads directly to the ring 318.

- This insulated wire 398 is supported by resinoid screw posts 39| and 392 screwed, respectively, into the block 388 and the member I19. The block 388 is cut away, as shown, and the wire 398 is well spaced from the metal except where it goes through the disk I15. In this way capacity in the high frequency circuits is held at a low figg the desired diameter at the same moment and then cause the head 63 to move upwardly carrying all of the honing tools out of the bores.

When starting the machine, the operator first throws the main reversing switch which receives current from the lines 251,, 252 to connect the center terminals 252, 258 to the poles 288, 288. This starts up the motor 33 in what may be called the positive direction. As a consequence thereof, the ball governor which includes the balls .285 expands and moves the collar 288 towards the gear 38. This draws the link III to the right (Figure 3) andopens the valve I22 provided the operator simultaneously pushes rearwardly the knob I51 to permit the valve to be moved. At this time or previously a switch (not'shown) for the motor 215: closed to actuate the fiuid pressure pump 8|. e solenoid I48 is unenergized on account of the position of the main reversing switch and, therefore, the spring I48 controls the rod H8. Due to this fact, the head will reciprocate in an idle upper position but at any time the operator can move the'hand lever H8 to allow the head 83 to move downwardly and then let it go again to continue the reciprocatory traverse in the lower or working position. All this time th push buttons 243 should be in so that the solenoids 235 are energized and there is no air pressure in the chambers 283. The hones, which had been contracted at the completion of the previous honing operation, will therefore remain contracted. Due to the lost motion connection between the rollers 295 and the groove 238, the traverse is slow but 2131: operator may speed it up by moving the lever It is now time to check the ammeters 383. The honing may be started first on the smallest bore, itbeing sufiicient to push the appropriate button 242. This admits air to the cylinder 283 because it opens a circuit and deenergizes a solenoid 235 and a particular hone is expanded.

When this smallest bore has been expanded to i again equal. Thus the operator controlsthe honing operation to keep all the bores at the same size during the enlargement thereof to final diameter. The operation is somewhat analogous to the geometrical proposition that when variables approaching their limits are always equal, their limits are equal. Thus when finally all the'bores arrive at the desired diameter, the operator will throw the main reversing switch to connect the center terminals 252 and 258 to the poles 288, 261, 269 and 218. The operator should make the change slowly so that the motor 38 will come to a stop before the current flows through theammeter in the reverse direction. As the motor 38 stops, the vertical traverse is brought to a stop by the automatic closing of the valve I22. Remembering that the air is on in all of the air brake chambers 283, when the motor starts up again in the reverse direction all the homes are contracted. Now the reason for the lost motion connection between the rollers 235 and the sides of the groove-.288,- will be clear. It is not desired that the reciprocatory traverse shoiild be recommended until the hones have been contracted to a substantial extent. By provision of the lost motion connection, the motor has run for an appreciable time before the valve I22 will be opened. 80; therefore, when the reciprocatory traverse is recommenced, the hones have already been collapsed. But by reason of the fact that the solenoid I40 is energized, the dog Ill does not strike the lug I and the head 00 continues upwardly, to be finally stopped by the closing again of the valve I22 by action of the cam surface I 00 on the pin I54. Then the operator would naturally pull the main reversing switch to the neutral position and press the buttons 243 inwardly to turn off the air in all of the air chambers 200 to take of! the brakes and the machine is ready for the next honing operation and when a new work piece 0 has been placed in position.

It will be noted that once a honing operation has started, shutting off of the air does not completely stop the honing action but it does slow it down. The pitch of the threads on the screw shaft I84 and the angle of the cones I00 are chosen so that the honing pressure from selfaction will not be too strong in order that the effect of the braking mechanism may make a real substantial difference. This, as will be seen, is a matter of selecting the pitch of the screw and the angle of the cones and in this respect the drawings should be considered merely diagrammatic.

It will be understood that boron carbide is a conductor to a slight extent. However, it is the equivalent of a resistance in the various circuits. It is advisable to leave some silver on the boron carbide movable contact member 302 which makes a good contact with the block 000. By scraping off the silver for a predetermined distance from the silvered slide 3", a known resistance is introduced into the circuit. This will not prevent the ammeters from being calibrated in terms of sizes of the bores. In fact, it is a means of adjustment for if the resistance in one circuit proves to be a little too low, more silver can be scraped off and vice versa. However, it will be understood that if desired an insulating sleeve may be provided in the block 000.

It will be noticed that the gauge means herein provided does not depend upon any purported absolute position of the work piece or of the tool or the bearing adjustments for either. Instead a direct measurement is made of the curvature of the work piece itself. If, for example, the work piece should happen to be badly out-ofround, a gauge would immediately disclose this information. In such cases the particular work piece might be set aside for reboring. It will be further observed that since boron carbide is very hard and can be brought to a high polish, no scratches will result on the surface of the work piece due to movement of the stationary contacts 3M and the movable contact 302 thereover.

It will thus be seen that there has been provided by this invention apparatus and a method in which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As many possible embodiments may be made of the above invention and as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limitin sense.

I claim:

1. In a honing machine, a central screw shaft, means rotatably to drive said screw shaft including means to reverse the direction of rotation, a hollow spindle surrounding said screw shaft, cage means connected to said hollow spindle supporting the honing sticks for expansion and contraction, honing-stick holders mounted in said cage means for movement in a generally radial direction, nuts in contact with said screw shaft, wedge means formed on said nuts and on said holders, and a brake to retard rotation of said cage means which is driven by said screwshaft through said nuts.

2. In apparatus of the class described, a honing tool, a slide mounted in said honing tool, stationary contact members on said slide, a movable contact member between said stationary contact members whereby if a bore becomes larger the movable contact member is displaced in the slide, a flat surface on said movable contact member and a stationary flat surface, each of said surfaces being conducting, a flexible dielectric between said surfaces whereby to form a condenser unit, electric connections from said honing tool, and electrical instruments to register a change in capacity of said condensers.

3. In a honing machine, a rotative drive, a plurality of honing tools, a head mounting said honing tools, means to reciprocate said head, connections between the rotative drive and the head and the honing toolsto rotate the honing tools while not reciprocating and while reciprocating, a stopping device to stop the reciprocation, and a governor connected to the rotative driving means and also connected to the device to stop the reciprocation whereby when the rotative drive is stopped the reciprocation will also stop.

4. In a honing machine, a motor, a reversing switch for said motor, a movable head, honing tool sockets ioumalled in said movable head, gearing including splined connections between said motor and said sockets whereby said sockets can be rotated both when the head is not reciprocating and while it is reciprocating, means to reciprocate said head including dogs to reciprocate the head in work position and means to move one dog to permit the head to be moved to a position remote from the working position,

gauging means and indicating apparatus indicating the size of each bore of a work piece operated upon by said machine, a plurality of honing tools in said sockets, and individual means to regulate the pressure of said honing tools in the bores and also to start the honing action, said means acting to contract said honing tools when the reversing switch is operated.

5. In a honing machine, means for holding work having a plurality of bores to' be honed, a plurality of expandable honing tools, one for each bore, means for reciprocating th tools axially of said bores, and individual means for rotating said tools to cause each to perform a honing operation upon its bore, means individual to each honing tool and operable during the drive of the tool to control the work done thereby including an inflatable friction member, and fluid means to inflate said members individually.

6. A honing machine comprising a rotatable and expansible honing tool, means to rotate the tool as a whole, means to reverse the direction of rotation of said tool, and means for controlling member movable radially of said honing tool and a member moving axially of said honing tool, said members being so related that upon rotation of the tool in one direction said members are actuated to expand the tool, and, upon rotation of the tool in the other direction, said members are actuated to contract said tool, pneumatically actuated brake means for controlling the speed of rotation of said tool in either direction, and remote control means therefor.

'I. In a honing machine comprising a reciprocable and rotatable and expansible honing tool, a honing tool frame, honing stick supports mounted in said frame, for movement radially thereof, and electro-responsive means, including a stationary contact member and a radially movable contact member carried by said frame and adapted to enter the bore of a workpiece and to measure its diameter, said movable contact member being slidably mounted in a bore in said frame and having a splined connection therewith and having a surface coating of a dielectric material between it and the body of said frame.

8. In a honing machine comprising a rotatable and expansible honing tool comprising a frame and honing stick supports mounted in said frame, electro-responsive means including a stationary contact member and a radially movable contact member carried by said frame, means forming an electrical capacitance between said radially movable contact member and said frame, and means forming an electrical circuit with said capacitance and having therein a source of potential for energizing said circuit, and translating means for translating the effect in said circuit of changes in capacity of said capacitance.

9. In a honing machine having an expansible honing tool comprising a frame for supporting a number of radially movable honing sticks, an electrical circuit including a capacitance comprising as one plate thereof a member carried by said frame and movable radially thereof, a rubber disk comprising another plate of said capacitance, interposed between said member and said frame, and a layer of silver carried by said member and thus interposed between said plates, said circuit having therein a source ofpotential for energizing said circuit, and translating means for translating the eflect in said circuit of changes in capacity of said capacitance.

10. In a honing machine, means for holding work having a plurality of bores to be honed, a plurality of expansible honing tools, one for each bore, means for rotating each of said honing tools individually, means for causing reciprocatory traverse of said honing tools in the bores of said work-piece, control means for said reciprocation causing means, and means actuated by the slowing down of the rotation of said honing tools for operating said control means to stop the reciprocatory traverse of said honing tools.

11. A honing machine comprising a head, means for reciprocating the head, a number of spindle sockets supported from said head, means for rotating the spindle sockets, a number of expandable hones supported on spindles from said sockets respectively, means individual to each hone for measuring the diameter of a work-piece bore in which it is inserted, means for simultaneously indicating the measurements assems made by all of the hones individually so that the operator may read and compare the sizes of the bores of a multi-bore work-piece, and control means for selectively expanding and contracting the bones individually so that the operator may bring all of the said bores to a desired diameter at the same moment.

12. A honing machine comprising a head, means for reciprocating the head, a number of spindles rotatably supported fromsaid head. each or said spindles having adjacent its free end an expandable hone adapted to be inserted in the bore of a work-piece to be ground, means individual to each hone for measuring the diameter of the bore in which it is inserted,'an indicating device having means thereon for recording the bore measurement made by each of said measuring means respectively, means for selectively expanding or collapsing the hones individually, and means for simultaneously withdrawing all of said hones from the respective bores in which they are inserted, whereby the several bores of a multi-bore work-piece may be ground simultaneously to different degrees and all of the hones withdrawn from all of the bores simultaneously when the indicating device indicates to the operator that all of the bores have attained a desired diameter.

13. A honing machine comprising a head, a number of spindles rotatably supported from said head, each of said spindles having adjacent its free end an expandable hone, and means governed by the direction and speed of rotation of said hones for controlling the expansion and contraction of said hones in the bores of a workpiece in which they are individually inserted, means individual to each hone for measuring and indicating the diameter of a bore in which the bone is inserted, means for inserting and withdrawing the said bones from the bores of said multi-bore work-piece simultaneously, and means for reversing the direction of rotation of said spindles simultaneously and for controlling the honing pressure ofrsaid hones in said bores individually for each bore whereby the operator during a given period, may grind the different bores of a work-piece to different degrees in accordance with the readings of said measuring means.

14. A honing machine comprising a head, means to reciprocate the head including dogs to reciprocate the head in work position, and means to move one dog to permit thehead to be moved to a position remote from the working position, means for stopping the head in said remote position, other means operable for stoppi reciprocation of the head at any time, a number of spindles rotatably supported from said head, means operable for stopping rotation of said spindles when the head is brought to a stop in said remote position, other means operable for controlling rotation of the spindles at any time, and means interconnected between said spindles and said head reciprocating means for stopping reciprocation of the head upon stopping of the rotation of said spindles.

15. A honing machine comprising a reciprocal head, a number of spindles rotatably supported from said head, means for controlling the reciprocation of the head including a displaceable member movable to change the direction of movement of said head, said displaceable member having a contact lug, three contact members movable into contact with said 1118, two of said contact members serving to control the normal work- 

